Langevin representation of laser heating in PIC simulations

An algorithm for inverse bremsstrahlung heating based on a Langevin equation, suitable for particle-in-cell (PIC) codes, is presented. We consider a quasi-neutral plasma with laser heating as described by inverse bremsstrahlung. This enables the inclusion of the heating without explicitly resolving the laser frequency and allows simulation of long time scale phenomena. Like and unlike particle collisions are included using a standard Monte Carlo procedure. The evolution of the distribution function in a homogeneous plasma is examined using this model and good agreement with theoretical predictions is achieved. This simulation model is a useful tool for the investigation of the evolution of the electron distribution and electron transport in inhomogeneous plasmas.